The invention relates in general to munitions and in particular to muzzle brakes for gun tubes such as large caliber cannons, artillery, howitzers, tanks, and smaller caliber guns such as .50 caliber machine guns and guns carried by a one person.
High-efficiency muzzle brakes used on large caliber weapons have low numbers (two or three) of baffles with relatively large areas. The low number of baffles results in rapidly increasing muzzle brake forces, thereby producing high amplitude and high frequency loads due to the large area of the baffles and their few numbers. As an example, the M-284 Muzzle Brake used on the M-109 Paladin and the XM-777 Muzzle Brake used on the LW-155 Towed Howitzer both use a two baffle brake with large areas. Analysis of the M-284 muzzle brake shows very abrupt and high load levels from the first baffle of the muzzle brake.
Most baffled muzzle brakes do not take into account the supersonic flow environment in muzzle brakes. Those muzzle brakes use geometries that may work well in subsonic flow environments, or use geometries not based on good aerodynamic principals, such as flat places or poorly curved surfaces. As a result, the improperly designed geometries produce unsteady or oscillating flow fields in the supersonic flow environment.
Conventional low-profile muzzle brakes have lower efficiencies than is sometimes necessary for operational use of cannons, particularly for lighter-weight vehicles that require low system impulse. Conventional low-profile muzzle brakes typically use a pepper pot muzzle brake like the Crusader with a muzzle brake gas dynamic efficiency of approximately 0.6, or a combination pepper pot and Laval nozzle configuration like the Denel LEO muzzle brake with a gas dynamic efficiency of approximately 0.56. Low-profile muzzle brakes are desirable due to reduced weight and better system integration. If there is some hardware that needs to fit around the muzzle brake, a low-profile brake is desirable. To obtain higher efficiencies, muzzle brakes often become very large, as is the case for the M-284 Muzzle Brake or the XM-777 Muzzle Brake.